Document 2Rrp1akEmgmev4pL06pD0g8wL

Title SOME RECENT ANALYTICAL DEVELOPMENTS IN RESPECT TO OR6ANOCHLORINE COMPOUNDS IN THE ENVIRONMENT '* Authors end heme of Institute: A, Richardson '`Shell" Research Limited, Tunstall Laboratory* SI tt Ingbourrre, Kent, England. Summary : In a study of the residues of organochlorIne Insecticides occurring In two species of aquatic birds, the heron (Ardea cIncrea)and the Shag (PhaUcrocorax arlstotells). compounds Interfering In the gas chromatography of the Insecticides were noted. These compounds may be separated from yBHC, heptachlor epoxide, dleldrln and endrin by liquid solid chromatography, but not from pp'-dl- chlorod1 phenyltrlchloroethene, pp'-DDT or Its metabolite pp*-dlchlorodlphenyldlchlof' ethylene, pp'-DDE. The Dohrmann mlcrocoulometrlc detector and thin layar chromatog raphy gave evidence that some of these compounds were halogenated and further their stability to strong acids and bases Indicated that they were probably chlorinated aromatic compounds. By means of combined gas liquid chromatography - mass spectros copy, these compounds were shown to be polychlorinated biphenyls. The occurrence of such compounds In the environment present serious problems In the analysis of tissues of humans and animals for chlorinated Insecticides. xxx Text: Environmental pollution with organochlorlne insecticides and their metabolites, particularly ODE, dleldrln, JDE and DDT, has been recognised for some years. Structural formulae of the most widely occurring compounds are given In Figure I. Recognition of the widespread occurrence of these compounds was chiefly due to the development of the electron capture detector In conjunction with gas-llquid chromatography. This technique provided a sensitive and semi-selective method for determination of thefe compounds (figure 2) . Semples ptovlded by the U.K. Nature Conservancy In connection with a study of the effect of organochlorlne Insecticide residues on aquatic predatory birds, In particular the shag (Phalacro- cotax arIstotelIs) and the heron (Ardea cinereal, gave, by electron capture detect ion, chromatograms In which other compounds Interfered with the determlnatIon of the Insecticides (Figure 3) . HONS 057431 However, mlcrocoulometrlc detect Ion following combustion when using silver Ion In acetic acid solution as tltrant (Figure 4) and thin layer chromatography Indicated the presence of halogenated compounds. Another group of chlorinated compounds widely used commercially as plasticisers and oil additives are the chlorinated biphenyls and following an Isolated report of the occurrence of such compounds in the environment we obtained samples of these from Monsanto. The chlorinated biphenyls are produced by the chlorination of biphenyl to give varying percentages of chlorine In the product, e,g. Arochfor 1254 contains 54% chlorine, and as such they consist of a range of compounds containing 3 to 7 chlorine atoms per biphenyl nucleus. Since Isomers occur there ere obviously a large number of compounds which may be present and this Is well Illustrated by the number of peaks In the chromatogram of Arochlor 1254 Shown In Figure 5* The rrlntlvf teieuMoh vnlumrs of sow- of 0>< < ns-pouitd*. flosply f:prrrr|*<ud to those of scour (him loatwl Insecticides (l Iguit () .. . page 2 Two biological samples which contained chlorinated compounds In addition to Insecticides have been examined In detail. These are herring oil and heron eggs. Chromatograms of these with both electron capture and mlcrocoulometrIc detection are given in Figures 7 and 8 respectively. Since the compounds are present In concentrations of one part per million or less, further advance in their characterisation required the use of a combination of gas-liquid chromatography and mass spectrometry. The samples were extracted with hexane and further cleaned up by partition with dimethyl formamlde, liquid-solid chromatography on FlorlsII and finally by treatment with concentrated sulphuric acid. The resulting hexene solutions were examined by GIC - HS using SE 30 as the liquid phase In the chrom atograph. The eluting gas was split 1:1, one half to a flame Ionisation detector, the other half to an MS 12 mass spectrometer fitted with a Blemann separator. The chromatogram of Arochior 1254 showed 10 main peeks. (Figure 9). Part of the mass spectra for peak 2, RRVDD- , n- 0*5 and peak 9, MV 1.84 respectively shows that peak 2 Is due to a compound of mass 2_30 f.C1 .35.) .wf.ileh contained 4 chlorine stoms and peak 9 Is that of a compound of mass 358 containing 6 chlorine atoms (Figure 10). The chromatogram for the heron egg wes likewise obtained (Figure II) . The mass spectra of peak 2 ftppr" 0.5 end peak 8 Rppc |.84 (Figure 12), show that the first compound contains 4 Cl and has a mass of 290 whilst the second contains $ Cl atoms. A precise mass was not obtained for this compound. The herring oil chromatogrem (Figure 13) was scanned on ten peeks. The mess spectra for peaks 4 and 10 Rqqe 0.8l and 1.85 respectively are shown in Figure 14. Peak 4 Is due to a mixture of 6 and 7 chlorinated compounds of messes 358 and 392 res pect Ively. A comparison of the relative retention times of these compounds occurring In herring oil end heron eggs (Figure 15) also supports the presence of chlorinated biphenyls as environmental pollutants. From these Investigations It Is apparent that the pollution of the environment by organochlorlne compounds other than Insecticides and their metab olites makes the InterpretetIon of gas-liquid chromatograms extremely difficult and further separation procedures will be required before the problem is solved. There Is a strong possibility that chlorinated naphthalenes and hexachloroben2ene may also occur In the environment which would complicate the Issue further* The problem iis an extremely practical one since to quote but one example, herring oil Is widely used In margarine manufacture end In some countries there are stringent regulatory limits as to the permitted levels of organochlorIne insecticides In foodstuffs. Obviously with the type of pollution described it Is virtually Impossible to pre cisely determine the level of some organochlorine insecticides with the methods currently at the disposal of the pesticide residue analyst. MQNS 057432